[jcnewbie]

I have milled a couple of slots around a cylinder using axis substitution and it works fine. However the problem I am having trying to understand is why does the cylinder have to be centered on the X axis? That is the only way I got it to work..

As well does someone have any more 4th axis, axis substitution files that I can practice on ?

[Superman]

Iwhy does the cylinder have to be centered on the X axis?

It doesn't,
your "model axis" can be any distance from the "rotary axis", but 99.99% of the time you would put the round work in a 3-jaw and on the same centre-line

Mastercam uses the "rotary axis line" as the pivot for the angle calculations

[Stebedeff]

I have had some problems with that as wel. All looks good in mastercam but the post just messes it up so machine does not do what it needs to do.
Sinds then I always use center of 4th axis as WCS.

[jcnewbie]

Thanks for the info..

When someone says that I have 3 +1 Machine, does that mean that the machine can rotate in x,y,z and has one extra axis , and that makes it a 4 axis machine ( positional ). And the same for 3+2 Machine, ?

If a machine can move in all 3 axis on top of the x,y,z, that makes it a 5 axis machine correct?

[Stebedeff]

I guess the 3+1 is a standard mill with and 4th axis. Usually set on the x-axis.
A 3+2 might be a tilting 4th axis which makes it possible to set the 4th to an angle and the rotate the "chuck" on the 4th axis.
Pretty much this is the first time I here of it.